US5124786A - Color signal enhancing cirucit for improving the resolution of picture signals - Google Patents

Color signal enhancing cirucit for improving the resolution of picture signals Download PDF

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Publication number
US5124786A
US5124786A US07/573,374 US57337490A US5124786A US 5124786 A US5124786 A US 5124786A US 57337490 A US57337490 A US 57337490A US 5124786 A US5124786 A US 5124786A
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Prior art keywords
color
signals
pair
signal
gain control
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Expired - Fee Related
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US07/573,374
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English (en)
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Hidemitsu Nikoh
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NEC Corp
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NEC Corp
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/64—Circuits for processing colour signals
    • H04N9/646—Circuits for processing colour signals for image enhancement, e.g. vertical detail restoration, cross-colour elimination, contour correction, chrominance trapping filters
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T3/00—Geometric image transformations in the plane of the image
    • G06T3/40—Scaling of whole images or parts thereof, e.g. expanding or contracting

Definitions

  • the present invention relates to a color-signal processing circuit and, more particularly, to a color-signal enhancing circuit which compensates color signals in electronic camera signal processing so that the deterioration in the resolution of the picture images is prevented.
  • the red, green and blue signals (hereinafter respectively referred to as "R”, “G” and “B") inputted to input terminals and the signals having passed through high-pass filters are respectively added by adders for effecting compensation of a deterioration of color signals for each color independently.
  • the problem in the conventional process referred to above is that, since the signals R, G and B are individually processed, when a change takes place only in the signal R, for example, among the signals R, G and B, there occurs a large change in the rising and falling of signal wave-forms of R alone. Thus, if the signals R, G and B are mixed at a predetermined ratio in order to produce a luminance signal and color difference signals ("R-Y" and "B-Y"), the balance of the color difference signals produced based on the signals R, G and B fluctuates thereby causing the appearance of a false color.
  • One of the main objects of the invention is to provide a color-signal enhancing circuit with which, without the primary-color signals R, G and B being processed independently, the mean value of certain frequency components of the color difference signals is obtained and, by a convertor, is converted into a single gain control signal which is used for effecting gain controlling of each of the color difference signals R-Y and B-Y.
  • This signal gain control signal can be relied upon for changing color saturation without changing the hue.
  • a color-signal enhancing circuit which comprises:
  • control circuit which receives outputs from the first and second frequency region restricting means and produces a gain control signal
  • a single gain control signal is obtained from the information of color difference signals R-Y, B-Y from such as an electronic camera and high frequency components or low frequency components thereof, the gains of the color difference signals R-Y, B-Y are similarly controlled by the use of the resultant single gain control signal, whereby it is possible to effectively enhance color signals in such a way that there will be no appearance of false colors at turning points of color changing.
  • FIG. 1 is a block diagram showing the configuration of a color-signal enhancing circuit according to a first embodiment of the present invention
  • FIG. 2 is a diagram showing a control circuit (CTL) in the circuit of the first embodiment shown in FIG. 1;
  • CTL control circuit
  • FIG. 3 is a timing chart showing the processing of the respective signals in the first embodiment shown in FIG. 1;
  • FIG. 4 is a block diagram showing the configuration of a color-signal enhancing circuit according to a second embodiment of the present invention.
  • FIG. 5 is a block diagram showing a conventional color-signal enhancing circuit.
  • FIG. 5 shows in a block diagram an example of a conventional color-signal enhancing circuit.
  • a signal from each of input terminals 31-33 and a signal having passed through each of high-pass filters 37-39 are added at each of adders 24-26 and the resultant signal is outputted from each of output terminals 34-36.
  • the input terminals 31-33 receive from a signal processing circuit in, for example, an electronic camera respective outputs of a red signal, a green signal and a blue signal (R, G and B) based on certain picture images.
  • a signal processing circuit in, for example, an electronic camera respective outputs of a red signal, a green signal and a blue signal (R, G and B) based on certain picture images.
  • Each of the high-pass filters 37-39 extracts high frequency components of each of the primary-color signals R, G and B.
  • Each of the resultant signals is added to each of the original signals by each of the adders 24-26.
  • the necessary compensation for a deterioration in the resolution is effected independently for each color. Reference to such a method is found in, for example, "TV Society Technology Report" TEBS 96-5, published May 24, 1984.
  • the present invention provides a color-signal enhancing circuit which overcomes the above problem and in which, without the primary-color signals R, G and B being treated, the mean value of certain frequency components of the color difference signals is extracted and then numerically converted into a single gain control signal by a circuit comprising a pair of filters, a pair of gain controllable amplifiers and a convertor, and the value of the resultant single gain control signal is used for gain controlling each of the color difference signals R-Y and B-Y. This enables to vary only the color saturation without changing the hue.
  • FIG. 1 shows in a block diagram a color-signal enhancing circuit of the first embodiment according to the present invention.
  • the circuit comprises a pair of input terminals 11, 12 receiving the respective input signals; a pair of high-pass filters 1, 2 connected to the respective input terminals 11, 12; a control circuit receiving the outputs of the filters 1, 2; and two multipliers 4, 5 for having the output of the control circuit 3 multiplied with each of the input signals inputted at the input terminals 11, 12 and outputting each of the resultant signals from a pair of output terminals 13, 14.
  • the pair of high-pass filters 1, 2 serve respectively as a pair of frequency region restricting means
  • the pair of multipliers 4, 5 serve respectively as a pair of gain control means.
  • FIG. 2 shows, in a block diagram, an example of the control circuit 3 in the circuit of FIG. 1.
  • This control circuit 3 comprises a pair of input terminals 15, 16; a pair of gain controllable amplifiers 21, 22 for giving a predetermined coefficient to each of the signals from the input terminals 15, 16; an adder 8 for adding up the respective outputs from the gain controllable amplifiers 21, 22; and a convertor 23 for giving a predetermined coefficient to the output of the adder 8 and outputting the resultant signal from an output terminal 17.
  • FIG. 3 shows a timing chart of the respective signals processed in the circuit shown in FIGS. 1 and 2, the numerals denoting signal levels of the digital signals.
  • signals J 1 , J 2 represent color difference signals which are inputted to the input terminals 11, 12; signals J 3 , J 4 represent signals which are outputted from the high-pass filters 1, 2; signals J 5 , J 6 represent signals which are outputted from the gain controllable amplifiers 21, 22; a signal J 7 represents a signal outputted from the adder 8, that is, the signal outputted from the control circuit 3; signals J 9 , J 10 represent signals outputted from the output terminals 13, 14; and signals J 11 , J 12 represent the hue and the amplitude of the color signals when the signal J 9 is B-Y and the signal J 10 is R-Y.
  • when the input is in the negative value and to output the signal J 8 1+J 7 /(J 7max ) when the input is in the positive value or 0 (zero).
  • J 7max is the maximum value which the signal J 7 can take.
  • the input signals J 1 , J 2 their high frequency components are extracted at the high-pass filters 1, 2.
  • These signals J 3 , J 4 of the high frequency components result in the signal J 7 after having passed the respective gain controllable amplifiers 21, 22 with their respective gains being controlled thereby and then having been added up at the adder 8. It means that the mean value of the signals J 3 , J 4 of the high frequency components is thus worked out by the gain controllable amplifiers 21, 22 and also the adder 8.
  • the signal J 7 is next converted into the signal J 8 at the convertor 23, which is inputted to the multipliers 4, 5 and with which the original signals J 1 , J 2 are multiplied, whereby the output signals J 9 , J 10 are obtained.
  • the original input signals J 1 , J 2 are gain-controlled by the mean value of the signals J 3 , J 4 of the high frequency components.
  • FIG. 4 shows, in a block diagram, a color-signal enhancing circuit of the second embodiment according to the present invention.
  • a pair of low-pass filters 6, 7 are used instead of a pair of the high-pass filters 1, 2 of the first embodiment shown in FIG. 1.
  • the remaining circuits other than these low-pass filters 6, 7 of this embodiment are the same as those of the above-explained first embodiment.
  • the signals J 1 , J 2 inputted to the input terminals 11, 12 pass through the low-pass filters 6, 7 where low frequency components of the signals are extracted, and the mean value thereof is obtained at the gain controllable amplifiers 21, 22 and also the adder 8.
  • the output from the convertor 23 is inputted to the multipliers 4, 5 where the inputted gain control signal J 8 is multiplied with each of the original input signals J 1 , J 2 .
  • the gain of the signal is controlled so as to be made small.

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  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Processing Of Color Television Signals (AREA)
  • Color Television Image Signal Generators (AREA)
US07/573,374 1989-08-30 1990-08-27 Color signal enhancing cirucit for improving the resolution of picture signals Expired - Fee Related US5124786A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP1-226091 1989-08-30
JP1226091A JPH0832056B2 (ja) 1989-08-30 1989-08-30 色信号強調回路

Publications (1)

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US5124786A true US5124786A (en) 1992-06-23

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US (1) US5124786A (de)
EP (1) EP0415350B1 (de)
JP (1) JPH0832056B2 (de)
DE (1) DE69013445T2 (de)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5337083A (en) * 1992-04-16 1994-08-09 Sanyo Electric Co., Ltd Digital video camera suppressing low-saturation chrominance
US5367340A (en) * 1990-10-19 1994-11-22 Gec-Marconi Limited Apparatus and method for noise reduction of video signal dependent upon video gain
US5374964A (en) * 1993-08-04 1994-12-20 Matsushita Electric Corporation Of America Circuit and method for controlling abnormally slow transitions in color television signals
US5987169A (en) * 1997-08-27 1999-11-16 Sharp Laboratories Of America, Inc. Method for improving chromatic text resolution in images with reduced chromatic bandwidth
US6078307A (en) * 1998-03-12 2000-06-20 Sharp Laboratories Of America, Inc. Method for increasing luminance resolution of color panel display systems
US6636647B1 (en) * 1998-06-17 2003-10-21 Sony Corporation Method and apparatus for merging data and medium for providing program for merging data
US20060017662A1 (en) * 2002-12-04 2006-01-26 Koninklijke Philips Electronics N.V. Method for improving the perceived resolution of a colour matrix display
CN105430231A (zh) * 2015-11-24 2016-03-23 努比亚技术有限公司 图像处理装置和方法

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1949352B1 (de) 2005-11-09 2013-10-16 InnoLux Corporation Verfahren und vorrichtung zur verarbeitung von pixel-signalen zum antreiben einer anzeige und anzeige damit
JP2007231490A (ja) * 2006-03-03 2007-09-13 Onward Kashiyama Co Ltd 衣服の裏地

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3816846A (en) * 1972-11-01 1974-06-11 Warwick Electronics Inc Hue correction system
US4337479A (en) * 1979-09-13 1982-06-29 Matsushita Electric Industrial Co., Ltd. Color resolution compensator
US4766487A (en) * 1986-08-13 1988-08-23 Sony Corporation Chrominance signal processing circuit
US4870481A (en) * 1987-12-01 1989-09-26 Ikegami Tsushiniki Co., Ltd. Color television signal transmission system and improved-definition receiver for use in the system

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5919671B2 (ja) * 1979-02-20 1984-05-08 松下電器産業株式会社 カラ−テレビジヨンカメラ
JPS6221393A (ja) * 1985-07-19 1987-01-29 Mitsubishi Electric Corp カラ−映像信号の色信号補正装置
JPH07121133B2 (ja) * 1986-10-03 1995-12-20 ソニー株式会社 輪郭補償回路
JPH01248782A (ja) * 1988-03-29 1989-10-04 Nec Corp 色信号アパーチャ補正回路

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3816846A (en) * 1972-11-01 1974-06-11 Warwick Electronics Inc Hue correction system
US4337479A (en) * 1979-09-13 1982-06-29 Matsushita Electric Industrial Co., Ltd. Color resolution compensator
US4766487A (en) * 1986-08-13 1988-08-23 Sony Corporation Chrominance signal processing circuit
US4870481A (en) * 1987-12-01 1989-09-26 Ikegami Tsushiniki Co., Ltd. Color television signal transmission system and improved-definition receiver for use in the system

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
"TV Society Technology Report", TEBS 96-5, publsihed May 24, 1984.
TV Society Technology Report , TEBS 96 5, publsihed May 24, 1984. *

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5367340A (en) * 1990-10-19 1994-11-22 Gec-Marconi Limited Apparatus and method for noise reduction of video signal dependent upon video gain
US5337083A (en) * 1992-04-16 1994-08-09 Sanyo Electric Co., Ltd Digital video camera suppressing low-saturation chrominance
US5374964A (en) * 1993-08-04 1994-12-20 Matsushita Electric Corporation Of America Circuit and method for controlling abnormally slow transitions in color television signals
US5987169A (en) * 1997-08-27 1999-11-16 Sharp Laboratories Of America, Inc. Method for improving chromatic text resolution in images with reduced chromatic bandwidth
US6078307A (en) * 1998-03-12 2000-06-20 Sharp Laboratories Of America, Inc. Method for increasing luminance resolution of color panel display systems
US6636647B1 (en) * 1998-06-17 2003-10-21 Sony Corporation Method and apparatus for merging data and medium for providing program for merging data
US20060017662A1 (en) * 2002-12-04 2006-01-26 Koninklijke Philips Electronics N.V. Method for improving the perceived resolution of a colour matrix display
CN105430231A (zh) * 2015-11-24 2016-03-23 努比亚技术有限公司 图像处理装置和方法
CN105430231B (zh) * 2015-11-24 2018-09-04 努比亚技术有限公司 图像处理装置和方法

Also Published As

Publication number Publication date
JPH0388492A (ja) 1991-04-12
DE69013445T2 (de) 1995-05-24
DE69013445D1 (de) 1994-11-24
EP0415350A2 (de) 1991-03-06
JPH0832056B2 (ja) 1996-03-27
EP0415350A3 (en) 1991-11-06
EP0415350B1 (de) 1994-10-19

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